Alpha-thalassemia

Alpha-thalassemia (α-thalassemia, α-thalassaemia) is an inherited blood disorder and a form of <a href="/facts/Thalassemia/NF7GIJsJ">thalassemia</a>. Thalassemias are a group of <a href="/facts/Genetic_disorder/hFqt2NLn">inherited</a> <a href="/facts/Blood_diseases/3238fyN7">blood conditions</a> which result in the impaired production of <a href="/facts/Hemoglobin/RsD1MzYA">hemoglobin</a>, the molecule that carries <a href="/facts/Oxygen/acyn6o8r">oxygen</a> in the blood. Symptoms depend on the extent to which hemoglobin is deficient, and include <a href="/facts/Anemia/AgEPPmg8">anemia</a>, <a href="/facts/Pallor/bHpLxohY">pallor</a>, <a href="/facts/Fatigue/C2oo4Hvg">tiredness</a>, <a href="/facts/Splenomegaly/hkB1jTdo">enlargement of the spleen</a>, <a href="/facts/Iron_overload/b7jEdAGr">iron overload</a>, abnormal bone structure, <a href="/facts/Jaundice/TCyoLMJU">jaundice</a>, and <a href="/facts/Gallstone/9bIB9MYT">gallstones</a>. In severe cases death ensues, often in infancy, or death of the unborn fetus.
The disease is characterised by reduced production of the <a href="/facts/Hemoglobin_subunit_alpha/Gb5sqdAy">alpha-globin</a> component of hemoglobin, caused by <a href="/facts/Genetic_disorder/hFqt2NLn">inherited</a> mutations affecting the genes <a href="/facts/HBA1/Gb5sqdAy">HBA1</a> and <a href="/facts/HBA2/lUSjvHGH">HBA2</a>. This causes reduced levels of hemoglobin leading to anemia, while the accumulation of surplus <a href="/facts/Hemoglobin_subunit_beta/qJRdFIWP">beta-globin</a>, the other structural component of hemoglobin, damages <a href="/facts/Red_blood_cell/Kggpq8Jh">red blood cells</a> and shortens their life. Diagnosis is by checking the medical history of near relatives, microscopic examination of <a href="/facts/Blood_smear/ao2R0t11">blood smear</a>, <a href="/facts/Ferritin/w7G85xJg">ferritin</a> test, <a href="/facts/Hemoglobin_electrophoresis/qbyy3Irb">hemoglobin electrophoresis</a>, and <a href="/facts/DNA_sequencing/hsPsNCQW">DNA sequencing</a>.
As an inherited condition, alpha thalassemia cannot be prevented although <a href="/facts/Genetic_counseling/IKbFotIe">genetic counselling</a> of parents prior to <a href="/facts/Fertilisation/g8u3UKzF">conception</a> can propose the use of <a href="/facts/Sperm_donation/zUbGPJJe">donor sperm</a> or <a href="/facts/Egg_donation/jv7npewL">eggs</a>. The principle form of management is blood transfusion every 3 to 4 weeks, which relieves the anemia but leads to iron overload and possible <a href="/facts/Immune_response/dtLulqIy">immune reaction</a>. Medication includes <a href="/facts/Folate/8Eb7An6D">folate</a> supplementation, <a href="/facts/Chelation_therapy/BtIB1o8I">iron chelation</a>, <a href="/facts/Bisphosphonate/s6po5jLd">bisphosphonates</a>, and <a href="/facts/Splenectomy/oFGhehpQ">removal of the spleen</a>. Alpha thalassemia can also be treated by <a href="/facts/Hematopoietic_stem_cell_transplantation/rGYRsATD">bone marrow transplant</a> from a well matched donor.
Thalassemias were first identified in severely sick children in 1925, with identification of alpha and beta subtypes in 1965. Alpha thalassemia has its greatest prevalence in populations originating from Southeast Asia, Mediterranean countries, Africa, the Middle East, India, and Central Asia. Having a mild form of alpha thalassemia has been demonstrated to <a href="/facts/Human_genetic_resistance_to_malaria/51fLxmA5">protect against malaria</a> and thus can be an advantage in malaria <a href="/facts/Endemic_(epidemiology)/YXHcRrQX">endemic</a> areas.

Alpha-thalassemia open-in-new

Alpha-thalassemia